1. Sprinkle salt and pepper on salmon.
2. Melt 1 T butter in medium skillet over medium-high heat.
3. (If you use a large skillet, you'll need to use more butter. For a better finished result, medium is preferred.) Add salmon; saute' until just opaque in the center, about four minutes per side if thick.
4. Transfer salmon to a plate.
5. Melt 1/2 T butter in same skillet.
6. Add 1/2 the shallots and half the tarragon; saute' 30 seconds.
7. Increase the heat to high; add half the spinach and toss 30 seconds.
8. Add remaining spinach and toss until wilted.
9. Divide the spinach between two plates.
10. Melt remaining 1/2 T butter in same skillet over medium-high heat.
11. Add remaining shallots and tarragon; saute' 30 seconds.
12. Add wine first and then cream and boil until the sauce is thick enough to coat a spoon, about 3 minutes (or less if using larger skillet).
13. Season with salt and pepper.
14. Return salmon to skillet; simmer 1 minute.
15. Arrange salmon with sauce atop spinach.
16. Serves two; can be doubled.